The failure mode variation in post-buckled GFRP columns with different stacking sequences - Experimental damage analysis and numerical prediction

Abstract

Fibre reinforced polymers are widely used materials in terms of their mechanical properties. The application of proper stacking-sequence of layers allows to obtain desirable properties of composite structure, and affect its failure mechanisms. The aim of this work was to evaluate the stacking sequence influence in the axially compressed glass-fibre reinforced epoxy thin-walled columns. To highlight the differences, the comparative failure analysis was performed. The macroscopic observation and the analysis of X-ray µCT images presented numerous damage types for particular stacking sequences. Also, the progressive failure analysis model, which takes the manufacturing conditions into account, was implemented. The novelty of the analysis approach lies in direct comparison of experimental and numerical results in scale 1:1 – both in macroscale and microscale. The analysis indicated the most sensitive points of the studied columns in terms of damage initiation. The most dominant failure mode was delamination. It was noted ply clustering allows one to limit the damaged area in cost of increased matrix failure. It was also noticed that symmetric and asymmetric stacking sequences possess insignificant differences in the damaged area. The changes of stacking sequences have the effect on the development of translaminar, interlaminar and intralaminar cracks likewise. The comparison of experimental failure analysis and finite element method showed that the PFA model predicts the approximate localization of the failures.